IIOHN EXPEDITIOX—MOLLUSCA. 
189 
much to be desired, with the view to better delimitation and more exact relation¬ 
ship to cognate groups. As a conchological group it exhibits a relation to 
Glypiorhagada^ through anigerens to such species of the latter as clydonigera^ 
which supply intergradations of shape and sculpture; nevertheless the typical 
members of the section have a complete peristome, whilst the peristome of 
Glyptorhagada is incomplete; subsecta and eyrei are not happily placed by Pilsbry 
in Angasella. 
Authentic specimens of A. cryptopleiira are not extant in any cabinet in 
Australia, so far as I know, and I cannot learn that the shell has been retaken or 
its accompanying congener, phillipsiana, at the original locality. Pfeiffer’s 
description is not detailed enough for safe delimination of allied species; but a 
shell, which I found numerous on the Bunda plateau of the Great Australian 
Bight, I had ventured to refer to his species. It presents the following char¬ 
acters :—The body-whorl much descends in front, and is ornamented with about 
sixty “ thread-like ribsthe intercostal spaces are coarsely granular, the granules 
having a tendency to coalesce to form rugie. The peristome is reflected and its 
margins united by a thick callus the elevation of the spire varies from almost 
flat to as much as 4‘5 mm. above the plane of the last whorl towards the front; 
the embryonic shell, which consists of one and a half turns, is relatively large and 
smooth. 
Diagnostic characters are furnished by the number and strength of the 
costie, taken iii conjunction with the build of the shell, though in this last respect 
the majority of the species approximate to a planorbiform contour. 
The well-developed periostracum, elevated into hairs, as possessed by 
A. setigera and its two allied species, imparts a new character to the group, and is 
suggestive of an alliance with Chloritis, though the embryonic shell of A. setigera 
is apparently smooth : in A. eiizyga and A. winneckeana it is, however, minutely 
granulated. 
Angasella setigera, Tate. (Plate XVII., Pig. 6.) 
Reference— Hadra setigera., Tate, Trans. Roy. Soc. S. Aust., vol. xviii., p. 
194, 1894. 
Shell depressed, somewhat planorbiform, spire very shortly elevated. Whorls 
flve, of moderate increase and of a low degree of convexity, separated by a deeply 
impressed linear suture. Last whorl very abruptly and far descending in front, 
somewhat widening in the anterior third, regularly convex from the suture to the 
